The invention relates to a releasable hubshaft-connection, in particular to be used in the construction of heavy machinery for transmitting strong torques. A typical connection of this type has at least one bore with its axis extending parallel to the axis of the shaft and penetrating the shaft with one half of its circumference and the hub with the other half. The bore is provided for accommodating a bushing having a cylindrical outer face and a conical inner face, wherein the bushing is expandible by means of a tapering bolt that is axially displaceable within the bushing.
Hitherto, in transmitting strong torques between the hub and shaft, press fit or tangential key connections have been used in the construction of heavy machinery, such as the construction of rolling mills and converters.
Press fits have the advantage that the hub and shaft can be quickly released and connected, and after a release no subsequent treatment is necessary for making a renewed connection. However, press fits have the disadvantage that their production is expensive and complex, since narrow tolerances have to be observed. Accordingly, often pieces are obtained which have to be rejected, thus increasing the costs of production.
When conventional tangential keys are used, disadvantages occur, which mainly consist in that, on the one hand, the assembly of the hub and shaft requires a fitting operation for the keys which takes a lot of time and, on the other hand, it is hardly possible to disassemble them. For a disassembly the keys have to be drilled out. If the hub is to be mounted again, new keys have to be fitted. A further disadvantage of the tangential key connection consists in that the sharp-edged notches in the shaft and the hub cause tension peaks, which require a wider diameter of the shaft and a thicker and stronger hub wall.
Furthermore, various hub-shaft connections have been known which are provided with bores along the periphery of the shaft that extend parallel to the axis of the shaft and which penetrate the shaft with one half their circumference and the hub with the other half. In these bores, clamping bolts are insertable consisting of a slit expanding bushing having a conical inner face and a central tapering pin which can be tightened relative to the bushing by a screw thread (German Offenlegungsschrift No. 24 45 252). Because of the slit expanding bushing, the clamping effect of the clamping bolt cannot be precisely determined. A large play is present between hub and shaft, and thus a precise centering of the hub on the shaft, as is necessary for toothed wheels, e.g., is very difficult. For releasing the hub-shaft connection, the tapering pin must be pushed out of the expanding bushing in the axial direction of the shaft by hammer blows. After an extended period of use, fitting rust can require forces for detaching the tapering bolts that are so strong that the tapering bolts or the bushings are damaged when being pushed out.